A collection of classes and commands for automated command line scripting using Python.
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# Imports
from commonkit import parse_jinja_template, read_file
from jinja2.exceptions import TemplateError, TemplateNotFound
import logging
import os
from ...constants import LOGGER_NAME
from .base import Command
log = logging.getLogger(LOGGER_NAME)
# Exports
__all__ = (
"Template",
)
# Classes
class Template(Command):
"""Parse a template."""
PARSER_JINJA = "jinja2"
PARSER_SIMPLE = "simple"
def __init__(self, source, target, backup=True, lines=False, parser=PARSER_JINJA, pythonic=False, **kwargs):
"""Initialize the command.
:param source: The template source file.
:type source: str
:param target: The path to the output file.
:type target: str
:param backup: Indicates a copy of an existing file should be madee.
:type backup: bool
:param parser: The parser to use.
:type parser: str
:param pythonic: Use a Python one-liner to write the file. Requires Python installation, obviously. This is
useful when the content of the file cannot be handled with a cat command; for example, shell
script templates.
:type pythonic: bool
"""
# Base parameters need to be captured, because all others are assumed to be switches for the management command.
self._kwargs = {
'comment': kwargs.pop("comment", None),
'cd': kwargs.pop("cd", None),
'environments': kwargs.pop("environments", None),
'function': kwargs.pop("function", None),
# 'local': kwargs.pop("local", False),
'name': "template",
'prefix': kwargs.pop("prefix", None),
'shell': kwargs.pop("shell", "/bin/bash"),
'stop': kwargs.pop("stop", False),
'sudo': kwargs.pop('sudo', False),
'tags': kwargs.pop("tags", None),
}
self.backup_enabled = backup
self.context = kwargs.pop("context", dict())
self.parser = parser or self.PARSER_JINJA
self.pythonic = pythonic
self.line_by_line = lines
self.locations = kwargs.pop("locations", list())
self.source = os.path.expanduser(source)
self.target = target
# Remaining kwargs are added to the context.
# print(_kwargs['comment'], kwargs)
self.context.update(kwargs)
super().__init__("# template: %s" % source, **self._kwargs)
def get_content(self):
"""Parse the template.
:rtype: str | None
"""
template = self.get_template()
if self.parser == self.PARSER_SIMPLE:
content = read_file(template)
for key, value in self.context.items():
replace = "$%s$" % key
content = content.replace(replace, str(value))
return content
try:
return parse_jinja_template(template, self.context)
except TemplateNotFound:
log.error("Template not found: %s" % template)
return None
except TemplateError as e:
log.error("Could not parse %s template: %s" % (template, e))
return None
def get_statement(self, cd=False, suppress_comment=False):
"""Override to get the statement based on the parser."""
if self.parser == self.PARSER_JINJA:
return self._get_jinja2_statement(cd=cd).statement
elif self.parser == self.PARSER_SIMPLE:
return self._get_simple_statement(cd=cd).statement
else:
log.error("Unknown or unsupported template parser: %s" % self.parser)
return None
def get_template(self):
"""Get the template path.
:rtype: str
"""
source = self.source
for location in self.locations:
_source = os.path.join(location, self.source)
if os.path.exists(_source):
return _source
return source
def _get_command(self, content):
"""Get the cat command."""
output = list()
# TODO: Template backup is not system safe, but is specific to bash.
if self.backup_enabled:
output.append('if [[ -f "%s" ]]; then mv %s %s.b; fi;' % (self.target, self.target, self.target))
if content.startswith("#!"):
_content = content.split("\n")
first_line = _content.pop(0)
output.append('echo "%s" > %s' % (first_line, self.target))
output.append("cat >> %s << EOF" % self.target)
output.append("\n".join(_content))
output.append("EOF")
else:
output.append("cat > %s << EOF" % self.target)
output.append(content)
output.append("EOF")
statement = "\n".join(output)
return Command(statement, **self._kwargs)
# # BUG: This still does not seem to work, possibly because a shell script includes EOF? The work around is to use
# # get_content(), self.target, and write the file manually.
# if self.line_by_line:
# a = list()
# a.append('touch %s' % self.target)
# for i in content.split("\n"):
# i = i.replace('"', r'\"')
# a.append('echo "%s" >> %s' % (i, self.target))
#
# output.append("\n".join(a))
# elif self.pythonic:
# target_file = File(self.target)
# script_file = "write_%s_template.py" % target_file.name.replace("-", "_")
#
# a = list()
# a.append('content = """%s' % content)
# a.append('"""')
# a.append("")
# a.append('with open("%s", "w") as f:' % self.target)
# a.append(' f.write(content)')
# a.append(' f.close()')
# a.append('')
# output.append('cat > %s <<EOF' % script_file)
# output.append("\n".join(a))
# output.append('EOF')
# output.append("")
# output.append("rm %s" % script_file)
# else:
# output.append("cat > %s << EOF" % self.target)
# output.append(content)
# output.append("EOF")
#
# statement = "\n".join(output)
# return Command(statement, **self._kwargs)
# noinspection PyUnusedLocal
def _get_jinja2_statement(self, cd=False):
"""Parse a Jinja2 template."""
content = self.get_content()
return self._get_command(content)
# noinspection PyUnusedLocal
def _get_simple_statement(self, cd=False):
"""Parse a "simple" template."""
content = self.get_content()
return self._get_command(content)